


Which Of Us Is The Devil?

by camichats



Category: Marvel
Genre: Assumptions, Bad Polyamory Etiquette, Established Bucky/Natasha, Exhibitionism, Explicit Sexual Content, F/M, Getting Together, Lack of Communication, Light Angst, Lingerie, M/M, Misunderstandings, Multi, Not Cheating, Oral Sex, Polyamory, Under-negotiated Kink
Language: English
Status: Completed
Published: 2019-06-12
Updated: 2019-06-12
Packaged: 2020-05-02 06:30:36
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,335
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/19193584
Author URL: https://archiveofourown.org/users/camichats/pseuds/camichats
Summary: Bucky and Nat cross the line from teasing Tony about their sex life, to being entirely inappropriate. Having sex with him wasn't really an improvement on that, but here they were.(for Winteriron bingo N3-Free Space)





	Which Of Us Is The Devil?

**Author's Note:**

> Originally title was "You and Me and The Devil Makes Three-- So Which Of Us Is The Devil?" but that was a bit long...
> 
> Please note that Bucky and Nat practice some very poor sex etiquette-- ie they have sex in front of Tony without getting his consent beforehand.

 There were times that Tony didn’t know what was going on, and he tended to hate those times with a passion because it meant someone was going to get hurt. Right now he didn’t have that problem, fortunately, but it was more confusing than whatever scheme the villain of the week was cooking up.

Natasha and Bucky were in a relationship, but they’d taken to teasing him about being between the two of them-- if it could even be called ‘teasing’ and not straight up ‘dirty talk’ or ‘exhibitionism’.

It had started simple enough. Bucky had said that Tony had the best ass he’d ever seen-- which was true, Tony knew there were entire websites about his posterior-- and instead of pretending to be offended, Nat had said, “Yeah I’d fuck him too. I’d imagine it feels even better when your dick’s real.”

“Woah Nat,” Clint said, because they had been on the comms in the middle of a fight, “I did not need to know that you peg the Winter Soldier.”

“Can we not?” Steve asked, voice strained.

“Don’t be a prude,” Nat said.

“I don’t want to hear about Bucky’s sex life, I had enough of that in the forties when I had to _see_ it.”

“Look pal, it’s not my fault that you’d get kicked outta pictures and come home early.”

Neither of them mentioned _that_ again-- although Tony could stand to here more about Bucky's life in the forties because it sounded hilarious-- so Tony wrote it off as a one time thing that was just normal battlefield discussion.

They’d teased in a similar vein one time on movie night, but they dropped it so they could actually watch the movie. Or, rather, so everyone else could watch it because Tony knew Nat wasn’t paying any attention with Bucky’s hand down her pants, and there was no way Tony couldn't _not_ notice because they were right next to him on the couch. It was technically a two person couch, but Tony hadn't thought anything of it at the time, what with Natasha dropping into Bucky's lap without a moment's hesitation.

When the movie ended, they didn’t even try to hide what they’d been doing from him while everyone else cleared out. Everyone else except Tony because they were in the living room on the penthouse floor instead of the one that the rest of the Avengers lived on (the tv down there waiting on a replacement from when a villain had set off Thor’s lightning and the tv had been an unfortunate casualty). He wasn't about to leave his own floor just because they were sticking around.

They didn’t stop when Tony turned on the lights, just stared at him heatedly. “Guys go to your room.”

“I don’t know Tony, I’m awfully comfortable.” There was an obscene bulge in her pants from Bucky’s hand, and it was obvious that Bucky had a couple fingers in her because there was no other way to explain why his hand wasn’t taking up a little more space. Natasha rolled her hips forward with a content hum.

“Yeah Tony, you want a couple fingers in you, all you gotta do is ask.”

“You don’t even have to ask nicely, he’d do it anyways. I’d offer but,” she held up her hand, showing off the sharp, fake nails that she was currently sporting, “I barely touch myself with these things, I’m not going to risk it with you.”

“Guys,” Tony grit out. “Go to your room.” He was holding one of the empty popcorn bowls in front of himself, and they definitely knew why, but he would be able to claim that this had nothing to do with them and more to do with the fact that they were having sex right in front of him.

Bucky sighed, kissing Natasha’s neck. “Fine.” He pulled his hand out, and his fingers were wet with her slick. Tony averted his eyes, upset that he’d been looking in the first place. He hated that they had used him as a part of their sex life without even asking. Granted, if they had asked he would have said yes, unable to deny either of them anything, but it was the principle of the matter. He wasn't even mad about that part, aware that between the two of them they probably didn't have the best etiquette when it came to sex involving not just the two of them.

That had been bad enough, yet it didn’t actually count in Tony’s head as their exhibitionist moment. That was reserved for the time he walked in on them fucking in the kitchen. It wasn’t even a spur of the moment thing for them because they were actually stripped naked and their clothes weren’t strewn about like they’d had to fling them aside in the throes of passion. It couldn’t even be an accident that none of the other Avengers were there except for Tony, or that Tony was going to the kitchen because he had to eat something every day at four o’clock since he’d gotten injured in the fight with the Wrecking Crew and that was too early in the day for anyone else to be in the kitchen.

They didn’t stop when he walked in, but then again, why would they? They’d planned this. Bucky didn’t even stop fucking her. They just looked over and Natasha threw her head back and groaned like it was turning her on.

Tony turned around and left, and none of them said anything. That was crossing a fucking line, and he hated that he was going to have to say something. God it was going to be like one of those workplace sexual harassment seminars where he told them that they were making him uncomfortable and please stop having sex in places that aren’t the privacy of their room.

He put it off for a few days, hoping that maybe he wouldn’t have to do it, but when neither of them apologized for the incident or said it wasn’t going to happen again, he knew that he couldn’t get away with saying nothing unless he wanted that to happen again. Did he want it to happen again?

No, he told himself firmly. They were both hot as all hell, and okay if there were porn of the two of them out there he would wank himself raw watching it, but he didn’t want this to keep happening. The fact that this was getting to him at all meant that he needed to get laid, but between Stark Industries and Iron Man, he didn’t have the time to find someone, and it’s not like he could just join Tinder or Grindr to take care of it.

He thought it would be easier to talk to just one of them rather than try and take them on at the same time. Nat was in the gym, by herself according to Jarvis, so Tony made his way over. He hated this. He hated having to fucking talk, he hated that it was about sex and he was going to sound like an eighty year old Puritan prick who couldn’t get it up anymore, and he hated that he’d been so distracted that he couldn’t get his project done and had to find her and get this dealt with just so he could focus again.

She was pummeling a punching bag when he walked in, and he hated that something not-sexy still turned him on. He blamed it on the fact that just a few days ago he’d seen how she looked while getting fucked.

Tony cleared his throat to get her attention, and she stopped, smiling brightly when she saw who it was.

“Hey.”

Tony swallowed. “Hey. Got a minute?”

“For you? Always.” She stepped away from the bag and started unwrapping her hands. “What’s up?”

“You and Bucky need to stop.”

“Stop what?”

“Having sex in common areas.”

“Getting a lot of complaints, are you.” She chuckled, shaking her head.

“Isn’t it enough that I don’t like it?”

Natasha paused. “I didn’t think you’d mind.”

“Why wouldn’t I mind? My teammates are fucking on the couch right in front of me and you expect me to be fine with it?”

“I expect you to be turned on by it considering the way you look at me.” She bundled the used tape into a ball in her hands, tossing it to the open faced trash can several feet away.

Tony flushed an ashamed red. “Anyone would be turned on if two attractive people were getting it on right in front of him; it doesn’t mean anything.”

“Doesn’t it?”

Tony grit his teeth. Did she have to embarrass him? Only instead of poking at his insecurities and the fact that he was far older than both of them, she reached her hand out and put it on his bare shoulder. Maybe he should have had this conversation with a shirt over his tank top. She slid her hand up his shoulder over to his neck, pulling him closer at the same time that she stepped in and kissed him.

He jerked back, staring at her with wide, betrayed eyes.

“Bucky knows,” she whispered. At his continued unease, she added, “I wouldn’t do that to either of you. It's okay.” She kissed him again, molding their lips together, and this time he didn’t pull away. She pressed herself up against him, and his hands went to her hips automatically.

“J seal it.” There was a small noise to indicate the locks clicking, but Tony didn’t notice as Natasha sucked on his bottom lip.

“Mmm always knew you’d be good with your mouth,” she moaned when Tony kissed at her neck.

Tony planned on going further, but she stepped away and laid on the mat, beckoning for him to join her before he even knew what was happening. He laid down on top of her, meaning to keep most of his weight off, but a well placed tug by Nat had him covering her from chest to thigh.

He was surprised she wanted him to be on top. As soon as he had the thought he paused. There was no way that was what she wanted, so if she’d pulled him onto her like she had, that meant she didn’t mean for them to fuck. He was okay with that, even though he couldn’t deny he was disappointed. He had one time with her and he didn’t get to know what she would feel like around his cock.

Like he said though, he was okay with that because he was going to get to find out what she tasted like, and he’d had more than one wet dream about her legs being wrapped around his head. Not wanting her to have to hurry him along, he shifted so his weight was on his knees between her legs. He unzipped her sports bra, and he wasn’t much of a tit worshipper, but god did they look perfect on her. He covered one with his mouth, licking at her nipple, then sucking on it when she put her hand on the back of his head to keep him in place.

“That’s good,” she said breathily, arching her back to push herself up into him. She muttered something in Russian before repeating, “That’s good.” Her skin was smooth under his mouth, her peaked nipple an unfamiliar texture-- one night stands didn’t lend themselves to much discovery-- and Tony craved it. She tasted like sweat and he wasn’t the least bit disgusted by it; he wanted to lick her all over and see if it would taste different in another place.

 _This isn't a date night_ , he reminded himself. She wasn't here for that, and like hell was he going to disappoint her. He didn't spend time exploring, but he also didn't rush. He kissed his way down her stomach and dipped his tongue in her bellybutton before nosing along the waistband of her tight exercise pants. She lifted her hips in invitation, so he pulled the pants down, enjoying the way she wiggled to get out of them more than he probably should have.

He thought about asking if she minded a few fingers in her, but he didn't want to bother her, and besides, she'd probably say no. He set her pants to the side and dove his head back down, pressing his tongue to her clit with firm strokes. Nat gasped and arched her back, so Tony kept doing what he was doing, switching it up when it seemed like she wasn't enjoying it as much anymore.

His jaw started to ache, but he ignored it. It's been a while since he's gone down on anyone, and he wasn't about to let this be ruined just because he'd lost a little of his resilience. He was getting spit and come on his chin, but he couldn't care less; there was a bathroom attached to the gym, he'd be able to wash up before anyone saw. And it was definitely worth it for the way Nat was rolling her hips and intermittently biting her lip. She moaned, muscles in her abdomen tightening, and Tony guessed that she was close.

Apparently, she was a lot closer than he'd thought because not a minute later she was unwrapping her legs from his shoulders and pushing at his forehead with her hand.

Tony sat back and wiped at his mouth with the back of his hand, but all that succeeded in doing was getting his hand messy.

"God look at you," Nat said, but Tony thought he couldn't compare to how she looked in that moment. Her lips were pinked and swollen, hair a mess from running her hand through it, breasts reddened from first Tony's touch and then her own, not to mention that her bra was hanging loosely from her shoulders since it had been unzipped from the front but not taken off, and her legs were spread wide, her cunt glistening from her slick and the hairless skin around it pink in irritation from Tony's beard.

Tony subconsciously wiped at his mouth again, then stuck the thumb from his clean hand over his shoulder. "I'm just gonna--" was all he said before fleeing to the bathroom. He locked the door behind him with no problem, but when he went to turn on the faucet, his hands were shaking.

It took a few minutes to get his hands and then his face clean, and by that point his erection had gone away. One less thing to worry about, at least. _She said that Bucky knows_ , he reminded himself. There was no need to panic. She'd just given him something he'd wanted to do for a long time, and they both enjoyed it. That was the best case scenario honestly, but here he was, hiding in the bathroom like he was ashamed. He sighed and splashed some water on his face, then walked out of the bathroom like he hadn't spent the last seven minutes freaking out.

Nat was waiting for him, redressed and leaning against the weight stand. "Hey," she said, straightening. "Are you okay?"

"Yeah I'm fine," Tony said, more than a little embarrassed. Her face cleared from worry and she prowled closer to him.

"You left before I could return the favor."

He cleared his throat, shifting uncomfortably, too busy not looking at her that he didn't see the frown she gave. "Yeah well. I wasn't going to ask you to do that." If this were a somewhat normal situation, this would be the part where he repeated what he'd come down to say, but asking her to stop doing sex-related things in front of him right after _they_ had sex seemed... a little ridiculous and hypocritical. For lack of anything else coming to mind, he said, "You're sure Bucky was okay with that?"

"Okay?" she said, raising an eyebrow. "Kotyonok, he's going to be positively green with envy. Which reminds me, you might want to keep an eye out for him."

Tony frowned, his brow furrowing. "What?"

She shrugged. "Now that I've had my turn, I'm sure he'll want his." With that, she winked at him and left, swaying her hips in a very self-satisfied way. "Oh and Tony?" she said, stopping in the doorway and looking back at him. "Don't even think about running off before he can get you to come, he'll hate that." She rolled her eyes. " _I_ hated it, but I suppose I didn't mention that in time." She winked again to let him know that she wasn't truly angry at him, then left.

Tony blinked numbly. Bucky was going to be doing this too? His fingers tingled, and he honestly couldn't have said if it was a good or a bad thing. He guessed he was going to find out soon enough.

He was undeniably nervous the next time he saw Bucky, years of people lying to him about the existence of their partners making the emotion deep rooted. But Bucky only smiled and asked him how his day had been.

* * *

Tony was sitting on the couch after getting home from a gala, tablet in his hands and in the beginning stages of undressed. His tie, jacket, and shoes were all off, but he'd only gotten the top button on his shirt undone before deciding that this was good enough.

"Hey doll."

Tony looked up to see Bucky standing several feet away, eyes taking in Tony's form like he was a dessert Bucky was planning on devouring and damn anyone that tried to stop him.

"Have fun?"

"No," he said honestly.

That didn't deter Bucky in the slightest. "Anythin' I can do to help?" he asked, but it was clear that he already had something in mind, stepping closer and getting on his knees in front of where Tony was sitting on the couch.

"Uh." Throat dry, Tony swallowed, but it didn't help any, not when Bucky was licking his lips and looking up at Tony like he was the best thing in the universe. "I take it Natasha's okay with this?" he asked, needing to make sure.

"Yep. She told me what a good time she had with you," Bucky said with a grin, leaning in to nuzzle at Tony's crotch.

" _Fuck_ ," Tony breathed, banging his head back against the cushion. He hadn't even noticed he was getting hard, but now it was impossible to ignore.

Bucky opened his mouth wide and put it against the outline of Tony's cock, closing it over his length like he was planning on sucking him down right through his pants. "Tony," he said reverently, using one hand to untuck Tony's shirt from his pants and following it with his mouth to get his lips on skin.

Tony felt a sudden rush of guilt that it was Bucky on his knees taking care of Tony like this was all about him. He got a hand on the back of Bucky's neck and pulled him up at the same time that he bent down, kissing him thoroughly. "Let's go to my room," he said when he broke away to pant for breath.

"Aw you mean you've never dreamed about gettin' blown here?"

Tony had, in fact, thought about that, but admitting that wouldn't help his cause so he kept it to himself. "I think," he said, tugging gently on the roots of Bucky's hair to see if he liked it-- Bucky's eyes fluttered and leaned into Tony more; yes, definitely liked it-- "that it would be better for you to fuck me on a bed than on the couch."

"We don't have to do that," Bucky said easily, sliding his hands down Tony's body and leaving a trail of sizzling fire in his wake. "I can just take you apart with my mouth right here. Won't even make a mess, scout's honor."

"You weren't a scout, and there's no point in us doing this if you aren't going to fuck me," Tony argued with a slight frown. Tony could suck him off of course, and while he was good at it, he doubted he was better than Natasha enough for it to matter. There was even less point if _Bucky_ was going to be the one on his knees.

"Whaddya mean no point? I'd get my mouth on you, that seems like a real nice point to me." Bucky demonstrated by going to Tony's neck and sucking lightly.

Tony shivered but had his wits about him enough to know that he needed to get them moving since apparently Bucky didn't realize what his own goal was in all this. "Come on," he said, managing to half-slither out from under Bucky and half-push him off so he could get to his feet. He had Bucky's hand in his, so he tried to pull him along as he made for his bedroom. Not that he got farther than a single step, because Bucky wasn't budging. Confused, Tony turned back to him.

"Are you always this rushed? I'd think you would understand the pros of takin' it nice and slow," he said with a smirk.

Tony had no idea why Bucky was being like this, but directly arguing with him probably wouldn't do anything good. "We can take it nice and slow on my _bed_." When Bucky still didn't move, thinking it over, Tony added, "If I get in some convoluted position I'm going to be in pain tomorrow, and I'll be thinking about that instead of the good part of this night."

"Darlin' you're gonna be thinking about _only_ me in the mornin'."

Tony didn't doubt that in the slightest, but he still didn't know what the hell was going on. All attempts to figure it out were like talking to a brick wall though, so he decided to let it go and just try and enjoy himself. Bucky made that _very_ easy for him.

* * *

Tony thought it would stop there. He'd been with Nat once, he'd been with Bucky once. If they were to be believed, they both had a great time. Neither of them mentioned sex for a while, but they were definitely sticking around more often and closer than they'd been doing before.

Until, of course, Tony was working on a watch that could turn into the Iron Man gauntlet, and Bucky and Natasha decided that they were going to visit him even though they were half dressed. Which is to say that Natasha was wearing a lace teddy, and Bucky was wearing a pair of tight boxer briefs.

Tony glanced up to see who was visiting him this late, then froze. Seriously, were they taking notes from porn? This was _ridiculous_.

"What are you working on?" Natasha asked, hopping up to sit on the table like this was an everyday situation.

Tony cleared his throat and looked down at the project in front of him, but it was hard to focus when Bucky came up next to him and was rubbing his back with one of his hands. "Does it matter?"

"Course it matters," Bucky said. "We'll probably see it in the field soon, we might as well know what it is."

But Tony just sighed, laying his hands flat on the tabletop. "Why are you doing this?"

"Being interested in your work? Well it tends to effect us since we work and live together, so..." Natasha trailed off with a smile like they were sharing an inside joke.

"There are better people you could be having a threesome with, if that's what you're looking for. And since you're both in fucking lingerie, I'm gonna say that's definitely what you're looking for. Try Steve, last I heard he was single."

Bucky snorted, his hand going up from Tony's back to play with the edges of his hair. "Yeah, only there's two problems with that. He's _Steve_ , and he's not you."

"Well then how about Clint?"

"Clint, seriously?" Nat said. "He's my best friend, but I'd never want to date him. He's cute and all but he's a goddamn mess."

"Who said anything about dating?" Tony asked, confused. "Clint used to be an acrobat, I'm pretty sure he's the dream person to borrow for a threesome."

Bucky's hand on Tony froze. "Uh, Tony? You know we want to date you, right?"

"What?"

"The sex, the flirting, showing up to your workshop half-naked..." Nat listed. "That's not exactly stuff friends do."

"Well no, but neither of you said anything."

"Really?" Bucky asked, brow creasing.

"I could've sworn I said something," Natasha added.

"Believe me," Tony said, "I'd remember."

She winced. "Oops? Although, that does explain a few things." How she managed to look sheepish while also fully comfortable with bare strips of lace covering her, Tony didn't know.

"This is what happens when we try and work separately," Bucky pointed out, and she nodded.

"Are you going to tell me what the fuck is going on?"

"We want to date you," Nat said.

"Y'know, fucking _and_ romance," Bucky added. "We thought you'd be more comfortable if we did it one at a time instead of together to start. Sorry that it didn't work out doll; we meant well."

Tony blinked, and maybe if he weren't so tired he would have said something snippy and gone to bed and not dealt with this for another couple days. But he _was_ tired, and just on the right side of loopy that he didn't care it might backfire. "It's okay. I'm uh, kinda wiped though, so why don't you go..." he trailed off and wiggled his fingers aimlessly to convey that they could go have sex without him, "and we can have breakfast tomorrow morning, just the three of us."

Natasha and Bucky shared a look before nodding. "Alright," she said, hopping off the table.

"See you tomorrow kitten," Bucky murmured, leaning down to press a kiss to the top of Tony's head.


End file.
